JP2012071012A - Endoscope device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope device capable of obtaining an optimal captured image of a microscopic blood vessel of a surface layer without making an operator intentionally adjust image processing and a light emission amount while observing a captured image in a special light observation.SOLUTION: The endoscope device includes a first light source part for emitting narrow band light, a second light source part for emitting wide band light, an imaging means for taking a captured image of a subject by the return light from a living body of the narrow and wide band light simultaneously applied to the subject from the first and second light sources to output captured image information, an image processing means for performing predetermined image processing to the captured image information, and an imaging information detecting means for detecting an automatic exposure value or imaging magnification for the imaging of the subject by the imaging means or subject information related to a structure and a component of the living body of the subject shot by the imaging means as imaging information. Light emission conditions and an image processing condition are changed on the basis of the detected imaging information.

Description

  The present invention relates to an endoscope apparatus capable of performing special light observation using broadband light such as white illumination light and specific narrowband light.

  In recent years, an endoscope apparatus that can perform so-called special light observation that irradiates a specific mucous tissue of a living body with specific narrow wavelength band light (narrowband light) and obtains tissue information of a desired depth of the living tissue has been utilized. Has been. This type of endoscope apparatus can easily visualize biological information that cannot be obtained by a normal observation image, such as a superficial fine structure of a new blood vessel generated in a mucosa layer or a submucosa layer, and emphasis on a lesioned part. For example, when the object to be observed is a cancerous lesion, if the mucosal tissue is irradiated with blue (B) narrow-band light, the state of the fine blood vessels and microstructures on the tissue surface layer can be observed in more detail, so that the lesion can be identified more accurately. Can be diagnosed.

On the other hand, the depth of light in the depth direction with respect to a living tissue depends on the wavelength of the light, and blue (B) light having a short wavelength is only deep in the vicinity of the surface layer due to absorption and scattering characteristics in the living tissue. Since it does not reach and is absorbed and scattered within a depth range up to that point, it can be observed as return light mainly including information on the surface layer structure. In the case of green (G) light having a longer wavelength than B light, Since it reaches deeper than the deepening range and is absorbed and scattered in that range, it can be observed as return light mainly containing information on the middle layer structure and surface layer structure, and has a red wavelength (R It is known that light can be observed as return light mainly including information on deep tissue and intermediate tissue because light reaches deeper tissue and is absorbed and scattered in that range.
That is, image signals obtained by receiving each return light obtained by irradiating B light, G light, and R light by an imaging sensor such as a CCD are mainly information on the surface layer tissue, mainly the middle layer tissue and the surface layer tissue, respectively. It is known to include the information of the deep layer structure and the medium layer structure.

  For this reason, in special light observation, in order to make it easier to observe the microvessels and microstructures on the tissue surface of the living tissue, it is mainly used for observing the middle and deep tissues of the living tissue as narrowband light irradiated to the living tissue. Without using suitable red (R) narrow-band light, blue (B) narrow-band light suitable for surface layer observation and green (G) narrow-band light suitable for middle layer and surface tissue observation Using only two types of narrow-band light, the image sensor can be obtained by irradiation with B narrow-band light, and the image sensor can be obtained by irradiation with B image signal (B narrow-band data) mainly including surface tissue information and G narrow-band light. Image processing is performed using only the obtained G image signal (G narrowband data) mainly including information on the middle layer tissue and the surface layer tissue, and a pseudo color image is displayed on a monitor or the like for observation.

Therefore, in the image processing, the G image signal (G narrow band data) obtained by the image sensor is assigned to the R image data of the color image by applying a predetermined coefficient, and each of the B image signals (B narrow band data) is predetermined. Is assigned to G image data and B image data of a color image, and a pseudo color image composed of 3ch (channel) color image data is generated and displayed on a monitor or the like.
For this reason, the image processing in the narrowband light mode for converting the two GB image signals obtained by receiving the return light by the narrowband light to the RGB color image data for pseudo color display on the display unit is as follows. This is different from the image processing in the normal light mode in which the three RGB image signals obtained by receiving the return light by the normal light by the image sensor are converted into RGB color image data for color display on the display unit. .

Also, in special light observation using R narrow band light, G narrow band light, and B narrow band light, R image signals (R narrow band data) are used for the purpose of observing microvessels and microstructures of the surface tissue. As described above, image processing is performed using only the G image signal and the B image signal, and a pseudo color image is displayed on a monitor or the like for observation.
In this case as well, in the image processing, similarly, the G image signal is assigned to the R image data, the B image signal is assigned to the G image data and the B image data, and a pseudo color image composed of 3ch color image data is generated and monitored. And so on.
As a result, in any case, the pseudo color image displayed on the monitor or the like mainly includes a lot of B image signals (B narrowband data) including information on the surface layer tissue. It is known that the state of the structure is expressed in more detail, and it becomes easier to observe the fine blood vessels and the fine structure of the surface tissue (see Patent Documents 1 and 2).

In the special light observation as described above, when the distance between the lesion tissue and the irradiation position of the special light is close, it is possible to image the fine blood vessels and fine structures on the tissue surface layer that are easy to see brightly. The problem of becoming difficult to see was known.
Further, as described above, when the distance between the lesion tissue and the irradiation position of the special light is changed and the enlargement ratio of the subject tissue is changed, and the pixel size of the blood vessel projected on the imaging device is changed, There was a known problem that made it difficult to recognize.
In addition, when the imaging position is separated, instead of each individual superficial microvessel, a dense area of superficial microvessels called brownish areas, each of which is an object to be observed, and an image to be applied to the captured image Although the processing is different, switching of these image processing is generally performed manually, and there is a problem that appropriate image enhancement is not necessarily performed.

Japanese Patent No. 3559755 Japanese Patent No. 3607857

  An object of the present invention is to observe surface light microvessels and the like without special adjustment of the light emission ratio of white light and special light such as the amount of emitted light and image processing while intentionally observing a captured image in special light observation. It is an object of the present invention to provide an endoscope apparatus that can obtain an optimal and bright captured image for observing the structure and components of a living body.

  In order to solve the above-described problem, the present invention provides a first light source unit that emits narrowband light having a narrowed wavelength bandwidth according to the spectral spectrum characteristics of the structure / component of a living body as a subject, A second light source that emits broadband light having a wide wavelength band including a visible region; and the narrowband light and the broadband light that are simultaneously irradiated onto the subject from the first light source unit and the second light source unit. The imaging unit that captures the captured image of the subject by the return light from the living body and outputs the captured image information, the image processing unit that performs predetermined image processing on the captured image information, and the imaging unit Imaging information detection means for detecting, as imaging information, automatic exposure value or imaging magnification for imaging a subject, or subject information related to the structure and components of the living body of the subject photographed by the imaging means The narrow-band light emitted from the first light source unit is more capable of detecting the structure / components of the living body of the subject than the broadband light emitted from the second light source unit. The first light source unit and the second light source unit so as to change the degree of detection and enhancement of the structure and components of the living body of the subject based on the photographing information detected by the photographing information detection unit. An endoscope apparatus characterized in that the light emission condition of the light source section and the image processing condition in the image processing section are changed.

  The present invention further provides the narrow-band light from the first light source unit and the broadband light from the second light source unit in order to change the light emission conditions of the first light source unit and the second light source unit. It is preferable to have a light emission ratio changing means for changing the light emission ratio.

  Further, the imaging information is the automatic exposure value, and the light emission ratio changing unit increases the light emission ratio of the narrowband light from the first light source unit when the automatic exposure value is small, and the automatic exposure. When the value is large, it is preferable to increase the emission ratio of the broadband light from the second light source unit, the imaging information is the imaging magnification, and the emission ratio changing means has a large imaging magnification. It is sometimes preferable to increase the emission ratio of the narrow-band light from the first light source unit, and to increase the emission ratio of the broadband light from the second light source unit when the imaging magnification is small.

  In addition, when the light emission ratio is changed by the light emission ratio changing unit, based on the light emission ratio, the electrical gain, the imaging time, and the imaging unit, so that the white balance of the captured image does not change It is preferable to change at least one of the color tone adjustments of the image processing, and when the light emission ratio is changed by the light emission ratio changing means, the light emission ratio is set so that the brightness of the captured image does not change. It is preferable to change at least one of an electrical gain, an imaging time, and a color tone adjustment of the image processing based on the imaging means.

  The image processing means preferably includes image enhancement means for changing frequency enhancement characteristics of the captured image based on the imaging information, and the image enhancement means enhances at least two frequency bands of the captured image. It is preferable that the frequency band emphasizing unit changes the frequency emphasis characteristic including changing the frequency band to be emphasized based on the imaging information.

  The imaging information is the automatic exposure value, and the frequency band emphasizing unit preferably changes the frequency band to be emphasized to a lower frequency as the automatic exposure value increases, and the imaging information Is the automatic exposure value, the frequency band emphasized by the frequency band emphasizing means is a band pass characteristic, and the frequency band emphasizing means emphasizes when the automatic exposure value exceeds a first predetermined value. It is preferable to change so as to increase the width of the frequency band.

  The imaging information is the automatic exposure value, and the frequency band emphasizing unit sets the frequency band to be emphasized to a band pass characteristic when the automatic exposure value is equal to or less than a second predetermined value, Preferably, the imaging information is the imaging magnification, and the frequency band emphasizing means increases the frequency band to be emphasized to a higher frequency as the imaging magnification increases. Preferably, the imaging information is the subject information related to the size of a brownish region or the thickness of a blood vessel, and the image enhancement unit is configured to change the size of the brownish region or the blood vessel. It is preferable to change the frequency enhancement characteristic of the captured image based on the thickness.

  The image enhancement means includes frequency band enhancement means for enhancing at least two frequency bands of the captured image, and the frequency band enhancement means is based on the size of the brownish region or the thickness of the blood vessel. Preferably, the frequency emphasis characteristic including changing the frequency band to be emphasized is changed, and the frequency band emphasizing means increases the frequency band to be emphasized to a higher frequency as the thickness of the blood vessel is reduced. Preferably, the frequency band emphasizing unit is configured such that when the size of the brownish area is equal to or smaller than a predetermined size, the frequency band to be emphasized has a bandpass characteristic, and the size of the brownish area is the predetermined area. When the size is exceeded, it is preferable to change so as to increase the width of the frequency band to be emphasized.

  The photographic information detection unit preferably detects the photographic information from the photographic image, and the photographic information detection unit preferably detects the automatic exposure value from the brightness of the photographic image.

  According to the endoscope apparatus of the present invention, in special light observation, automatic exposure value or imaging magnification necessary for photographing a living body as a subject, or subject information related to the structure / component of the photographed living body is detected as imaging information. Based on the detected shooting information, the emission conditions of the special light source and the white illumination light source and the image processing conditions of the captured image are changed so as to change the detection and enhancement degree of the structure / component of the living body. When observing light, for example, when the lesion is enlarged or imaged from the proximal side and the superficial microvessels are observed, the lesion is imaged from the distal side, and a dense brownish region of the superficial microvessels is observed. When observing, it is not necessary for the operator to intentionally adjust or change the light emission conditions of these light sources and the image processing conditions of the captured image while observing the captured image. It is possible to obtain an optimal and bright captured image to the optical observation.

It is a block diagram showing typically an example of the whole composition of the endoscope apparatus of one embodiment of the present invention. 1 shows emission spectra of narrow-band light emitted from a narrow-band laser light source used in the light source unit of the endoscope apparatus shown in FIG. 1 and pseudo-white light emitted from a white light source composed of a blue laser light source and a phosphor. It is a graph. It is a block diagram which shows the signal processing system of each part containing the detailed structure of one Example of the processor of the endoscope apparatus shown in FIG. It is a graph which shows one Example of the table which prescribes | regulates the relationship between the automatic exposure (AE) value and laser (LD) light quantity ratio with which the required light quantity ratio calculation part shown in FIG. 3 is provided. It is a graph which shows one Example of the frequency emphasis filter with which the structure emphasis part of the special light image process part shown in FIG. 3 is provided. It is a flowchart which shows the flow of one Example of the narrow-band light observation implemented with the endoscope apparatus shown in FIG.

An endoscope apparatus according to the present invention will be described in detail below based on a preferred embodiment shown in the accompanying drawings.
FIG. 1 is a block diagram schematically showing an example of the overall configuration of an endoscope apparatus according to an embodiment of the present invention.
As shown in FIG. 1, the endoscope apparatus 10 of the present invention includes an endoscope 12, a light source unit 14, a processor 16, and an input / output unit 18. Here, the light source unit 14 and the processor 16 constitute a control device for the endoscope 12, and the endoscope 12 is optically connected to the light source unit 14 and electrically connected to the processor 16. The processor 16 is electrically connected to the input / output unit 18. The input / output unit 18 includes a display unit (monitor) 38 that outputs and displays image information and the like, a recording unit (recording device) 42 (see FIG. 3) that outputs image information and the like, and a normal observation mode (normal light mode). And an input unit (mode switching unit) 40 that functions as a UI (user interface) that receives input operations such as mode switching and function setting such as special light observation mode (also referred to as special light mode).

  The endoscope 12 is an electronic endoscope having an illumination optical system that emits illumination light from the tip thereof and an imaging optical system that images an observation region. Although not shown, the endoscope 12 includes an endoscope insertion portion that is inserted into the subject, an operation portion that performs an operation for bending and observing the distal end of the endoscope insertion portion, and an endoscope. A connector unit is provided that detachably connects the mirror 12 to the light source unit 14 and the processor 16 of the control device. Further, although not shown, various channels such as a forceps channel for inserting a tissue collection treatment instrument and the like and a channel for air supply / water supply are provided inside the operation unit and the endoscope insertion unit.

  As shown in FIG. 1, the distal end portion of the endoscope 12 dictates the details of the irradiation port 28A for irradiating light to the observation region. However, the phosphor constituting the illumination optical system and constituting the white light source is described. And an image sensor (sensor) such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) image sensor that acquires image information of the observation region in the light receiving unit 28B adjacent to the irradiation port 28A. 26 is arranged. A cover glass and a lens (not shown) constituting the irradiation optical system are arranged at the irradiation port 28A of the endoscope 12, and a cover glass and a lens (not shown) constituting the illumination optical system are arranged at the light receiving unit 28B. ) And an objective lens unit (not shown) constituting the imaging optical system is arranged on the light receiving surface of the image pickup device 26 of the light receiving unit 28B.

The objective lens unit includes an objective lens (not shown). The angle of view (viewing angle) of the objective lens is uniquely determined by the size and focal length of the lens, and the captured image formed by the imaging optical system becomes larger as the tip of the endoscope 12 approaches the subject, and when it moves away. Therefore, the imaging magnification that is the magnification between the subject and the captured image at the time of subject imaging can be obtained from the angle of view of the captured image.
Although the photographing magnification can be obtained in this way, the method for obtaining the photographing magnification is not limited to this, and various methods can be used.
For example, as disclosed in Japanese Patent Laid-Open No. 2000-230807, parallel light parallel to the optical axis of the imaging optical system is irradiated from the illumination optical system to the subject by a laser or the like, and an image is formed on the imaging optical system by the return light. By measuring the length of the real image with respect to the imaging field, the imaging magnification can be automatically detected.
Further, the objective lens unit is provided with an imaging lens (not shown) that is movable in the optical axis direction and a lens driving mechanism (not shown) that moves the imaging lens in order to change the imaging magnification. You may have a magnification photographing mechanism. In this case, the lens driving mechanism is composed of an actuator composed of, for example, a piezoelectric element, and the imaging magnification can be further changed by moving the imaging lens in the optical axis direction.

The endoscope insertion section can be bent by the operation of the operation section, and can be bent in an arbitrary direction and an arbitrary angle according to the part of the subject in which the endoscope 12 is used. The portion 28B, that is, the observation direction of the image sensor 26 can be directed to a desired observation site.
The image sensor 26 is preferably a color image sensor or a complementary color sensor provided with a color filter (for example, an RGB color filter or a complementary color filter) in the light receiving region, but an RGB color image sensor is more preferable.

The light source unit 14 includes a blue laser light source (445LD) 32 having a central wavelength of 445 nm used as a light source for white illumination light used in both the normal light mode and the special light mode, and a central wavelength used as a special light source in the special light mode. A 405 nm blue-violet laser light source (405LD) 34 is provided as a light source. The blue-violet laser light having a center wavelength of 405 nm from the blue-violet laser light source 34 is preferably a narrow-band light having a narrowed wavelength bandwidth in accordance with the spectral spectrum characteristics of the structure and components of the living body. Therefore, the ability to detect the structure and components of the living body is excellent.
Light emission from the semiconductor light emitting elements of the light sources 32 and 34 is individually controlled by a light source control unit 48 (see FIG. 3), and the light emission conditions of the light sources 32 and 34, that is, the emitted light of the blue laser light source 32 and The light quantity ratio (light emission ratio) of the emitted light from the blue-violet laser light source 34 is freely changeable.
As the blue laser light source 32 and the blue-violet laser light source 34, a broad area type InGaN laser diode can be used, and an InGaNAs laser diode or a GaNAs laser diode can also be used. In addition, a light-emitting body such as a light-emitting diode may be used as the light source.

Laser light emitted from each of the light sources 32 and 34 is input to the optical fiber 22 by a condenser lens (not shown), and transmitted to the connector portion via a multiplexer (not shown). In addition, this invention is not limited to this, The structure which sends out each laser beam from each light source 32, 34 directly to a connector part, without using a multiplexer may be sufficient.
The laser beam combined with the blue laser beam having the center wavelength of 445 nm and the blue-violet laser beam having the center wavelength of 405 nm and transmitted to the connector unit is respectively connected to the distal end portion of the endoscope 12 by the optical fiber 22 constituting the illumination optical system. Is propagated to. Then, the blue laser light excites the phosphor 24 that is a wavelength conversion member disposed at the light emitting end of the optical fiber 22 at the distal end of the endoscope 12 to emit fluorescence. Some of the blue laser light passes through the phosphor 24 as it is. The blue-violet laser light is transmitted without exciting the phosphor 24 and becomes illumination light with a narrow band wavelength (so-called narrow band light).
The optical fiber 22 is a multimode fiber. As an example, a thin fiber cable having a core diameter of 105 μm, a cladding diameter of 125 μm, and a diameter including a protective layer serving as an outer shell of φ0.3 to 0.5 mm can be used.

The phosphor 24 includes a plurality of types of phosphors (for example, YAG-based phosphors or phosphors such as BAM (BaMgAl ₁₀ O ₁₇ )) that absorb part of blue laser light and excite and emit green to yellow light. Consists of. As a result, green to yellow excitation light using blue laser light as excitation light and blue laser light transmitted without being absorbed by the phosphor 24 are combined into white (pseudo-white) illumination light. If a semiconductor light-emitting element is used as an excitation light source as in this configuration example, high-intensity white light can be obtained with high luminous efficiency, the intensity of white light can be easily adjusted, and the color temperature and chromaticity of white light can be adjusted. Can be kept small.
The phosphor 24 described above can prevent the occurrence of flickering when performing moving image display due to speckles caused by the coherence of the laser light, which may cause noise superposition and a moving image display. Further, the phosphor 24 takes into account the difference in refractive index between the phosphor constituting the phosphor and the fixing / solidifying resin serving as the filler, and the particle size of the phosphor itself and the filler is set to the light in the infrared region. In contrast, it is preferable to use a material that has low absorption and high scattering. This enhances the scattering effect without reducing the light intensity for red or infrared light, and reduces the optical loss.

FIG. 2 is a graph showing the blue-violet laser light from the blue-violet laser light source 34, the blue laser light from the blue laser light source 32, and the emission spectrum obtained by wavelength conversion of the blue laser light by the phosphor 24. The blue-violet laser light is represented by a bright line (profile A) having a center wavelength of 405 nm, is the narrow band light of the present invention, and becomes special light. The blue laser light is represented by a bright line having a center wavelength of 445 nm, and the excitation light emitted from the phosphor 24 by the blue laser light has a spectral intensity distribution in which the emission intensity increases in a wavelength band of approximately 450 nm to 700 nm. The above-described pseudo white light is formed by the profile B of the excitation light and the blue laser light, and becomes normal light.
Here, the white light as used in the present invention is not strictly limited to the one containing all the wavelength components of visible light. For example, a specific wavelength such as the above-described pseudo white light, R, G, B, etc. For example, light including a wavelength component from green to red, light including a wavelength component from blue to green, and the like are included in a broad sense.
In the endoscope apparatus 10, the light emission intensity of the profile A and the profile B can be relatively increased / decreased by the light source control unit 48 to generate an irradiation port having an arbitrary luminance balance. In the endoscope apparatus 10 of the present invention, only the light of the profile B is used in the normal light mode, and the light on which the profiles A and B are superimposed is used in the special light mode.

As described above, from the blue laser light from the blue laser light source (hereinafter referred to as 445LD) 32 and the white light (profile B) generated by the excitation light emitted from the phosphor 24, and from the blue-violet laser light source (hereinafter referred to as 405LD) 34. Illumination light (profile A) composed of narrow-band light by blue-violet laser light is emitted from the irradiation port 28A at the distal end of the endoscope 12 toward the observation area of the subject. Then, the return light from the observation region irradiated with the illumination light is imaged on the light receiving surface of the image sensor 26 through the light receiving unit 28B, and the image pickup device 26 images the observation region.
An image signal of a captured image output from the image sensor 26 after imaging is input to the image processing system 36 of the processor 16 through the scope cable 30.

Next, the image signal of the picked-up image picked up by the image pickup device 26 in this way is subjected to image processing by a signal processing system including the image processing system 36 of the processor 16 and output to the monitor 38 and the recording device 42 for observation by the user. Is done.
FIG. 3 is a block diagram showing a signal processing system of each part including a detailed configuration of an embodiment of the processor of the endoscope apparatus of the present invention.
As shown in the figure, the signal processing system of the endoscope apparatus 10 includes a signal processing system of the endoscope 12, a signal processing system of the light source unit 14, and a signal processing system (image processing system 36) of the processor 16. A monitor 38 of the input / output unit 18, an input unit (mode switching unit) 40, and a recording device 42.

The signal processing system of the endoscope 12 is a signal processing system of an image signal of a captured image from the image sensor 26 after imaging, and is correlated double sampling (CDS) or automatic gain control (AGC) to a captured image signal that is an analog signal. And an A / D converter (A / D converter) 46 for converting the analog image signal sampled and gain-controlled by the CDS / AGC circuit 44 into a digital image signal. . The digital image signal A / D converted by the A / D converter 46 is input to the image processing system 36 of the processor 16 through the connector unit.
The signal processing system of the light source unit 14 includes a light source control unit 48 that performs on / off control and light amount control of the blue laser light source (445LD) 32 and the blue-violet laser light source (405LD) 34.

  Here, the light source control unit 48 turns on the blue laser light source 32 according to the light source ON signal accompanying the start of operation of the endoscope apparatus 10, or switches between the normal light mode and the special light mode from the mode switching unit 40. Depending on the signal, on / off control of the blue-violet laser light source 34 is performed, and the blue light and the G light amount of the image calculated from the light amount calculation unit 50 described later, the emission intensity of the profiles A and B, etc. The light emission intensity of the laser light source 32 and the blue-violet laser light source 34, that is, the value of the current passed through the light sources 32 and 34 is controlled. That is, the light source control unit 48, together with a required light amount ratio calculation unit 58, which will be described later, an automatic exposure (AE) value (light amount value) detected by a shooting information detection unit 56, a shooting magnification, or the size of the brownish area, It functions as a light emission ratio changing means for changing the light emission conditions of both the light sources 32 and 34, that is, the light emission ratio, based on imaging information such as subject information relating to the structure and components of a living body such as the thickness of a blood vessel.

Further, the signal processing system of the processor 16 is an image processing system 36 (see FIG. 1), and includes a light amount calculation unit 50, a DSP (digital signal processor) 52, a noise removal circuit 54, and an image processing switching unit (switch). ) 60, a normal light image processing unit 62, a special light image processing unit 64, and an image display signal generation unit 66.
The light amount calculation unit 50 uses the digital image signal input from the A / D converter 46 of the endoscope 12 via the connector, and the amount of return light received by the image sensor 26, for example, the amount of B light and The amount of G light, that is, the amount of B light and G light of the image is calculated. Then, the light amount calculation unit 50 calculates a light amount ratio (B / G ratio) between the B light and the G light of the captured image based on the calculated B light and G light amounts of the image.

Further, the light quantity calculation unit 50 further supplies the light source quantity, that is, the quantity of blue laser light from the 445LD 32 (light emission intensity) and the quantity of pseudo white light from the phosphor 24 by the blue laser light (profile B shown in FIG. 2). Emission intensity), the amount of blue-violet laser light from 405LD34 (emission intensity of profile A shown in FIG. 2), and the like. Ask.
Then, the light amount calculation unit 50 calculates the brightness (luminance value) of the captured image based on the calculated RGB value of the captured image, and together with the light amount and the light amount ratio (405LD / 445LD light emission ratio) of 445LD32 and 405LD34. And output to the photographing information detection unit 56.

The imaging information detection unit 56 calculates imaging information based on the calculated light amounts of 445LD32 and 405LD34 and a light amount ratio (light emission ratio). Here, the photographing information relates to the structure / components of a living body such as an automatic exposure (AE) value (light quantity value) for photographing a subject (living body), a photographing magnification, or the size of a brownish region and the thickness of a blood vessel. Subject information and the like can be increased.
Here, the automatic exposure value (AE value) is a parameter for automatically determining the exposure at the time of imaging, and is determined based on the amount of light (brightness) of the return light detected by the image sensor 26. The Also in moving image shooting, it is determined by the amount of return light in the shooting time per frame that is determined according to the storage time of the image sensor 26 (the storage time of the CCD or CMOS corresponding to the RGB color filter).

The imaging magnification can be obtained from the angle of view of the captured image as described above, and is usually automatically detected as described above. Furthermore, when the imaging optical system has a high-magnification photographing mechanism, the imaging magnification is changed according to the distance between the objective lens and the imaging lens.
The subject information refers to the structure and components of the living body such as the size of the area where the superficial microvessels such as lesions in close-up photography are dense, that is, the brownish brownish area size and the size of individual blood vessels in enlarged photography and close-up photography. It is information about. The size or blood vessel thickness of the brownish region is detected by extracting a brownish brownish region from the captured image or extracting individual blood vessels. For the extraction of the brownish region, various known methods for detecting the color and shape can be used. In the present invention, it is preferable that the image processing applied to the captured image is changed when the size or blood vessel thickness of the detected brownish region in the captured image changes.
When these pieces of shooting information are detected, they are output to the required light amount ratio calculation unit 58 and a special light image processing unit 64 described later.

The necessary light amount ratio calculating unit 58 calculates the light amount ratio and the light amount necessary for photographing based on the photographing information detected by the photographing information detecting unit 56. The required light quantity ratio calculation unit 58 has, for example, a table showing the relationship between the AE value and the 405LD / 445LD light quantity ratio as shown in FIG. 4, and the 405LD / 445LD light quantity ratio based on the AE value that is photographing information and this table. And the amount of light of 405LD and 445LD is also calculated.
The calculated light amounts and light amount ratios of 405 LD and 445 LD are output to the light source control unit 48.
When the laser light quantity ratio changes, the white balance of the captured image also changes. Therefore, the light quantity and the light quantity ratio of 405LD and 445LD are output to the CDS / AGC circuit 44, and the white balance is based on the information on the light quantity and the light quantity ratio. The gain of the CDS / AGC circuit 44 for taking the image is also changed, and the electrical gain of the image sensor 26 is changed.

The DSP 52 (digital signal processor) performs gamma correction and color correction processing on the digital image signal output from the A / D converter 46 after the light source light amount is detected by the light amount calculation unit 50.
The noise removal circuit 54 removes noise from a digital image signal that has been subjected to gamma correction and color correction processing by the DSP 52 by performing a noise removal method in image processing such as a moving average method and a median filter method.
In this way, the digital image signal input from the endoscope 12 to the processor 16 is subjected to preprocessing such as gamma correction, color correction processing, and noise removal by the DSP 52 and the noise removal circuit 54.

The image processing switching unit 60 sends a digital image signal preprocessed based on an instruction (switching signal) from a mode switching unit (input unit) described later to the normal light image processing unit 62 at the subsequent stage, or a special light image processing unit. 64 is a switch for switching to 64.
In the present invention, for distinction, the digital image signal before image processing by the normal light image processing unit 62 and the special light image processing unit 64 is referred to as an image signal, and the digital image signal before and after the image processing is referred to as image data. I will decide.
The normal light image processing unit 62 performs image processing for normal light suitable for the preprocessed digital image signal by the white light (profile B) by the 445LD and the phosphor 26 in the normal light mode. 68, a color enhancement unit 70, and a structure enhancement unit 72.

The color conversion unit 68 performs color conversion processing such as 3 × 3 matrix processing, gradation conversion processing, and three-dimensional LUT processing on the preprocessed RGB 3 channel digital image signal, and converts the color converted RGB image data into Convert.
The color emphasizing unit 70 is for emphasizing the blood vessels by making a difference in color between the blood vessels and the mucous membrane in the screen so that the blood vessels can be easily seen. For example, a process of looking at an average color tone of the entire screen and emphasizing the color tone in a direction of adding a color difference between the blood vessel and the mucous membrane from the average value is performed.
The structure enhancement unit 72 performs structure enhancement processing such as sharpness and contour enhancement on the color enhancement processed RGB image data.
The RGB image data subjected to the structure enhancement processing by the structure enhancement unit 72 is input from the normal light image processing unit 62 to the image display signal generation unit 66 as normal light image processed RGB image data.

The special light image processing unit 64 is special light suitable for preprocessed digital image signals by blue-violet laser light (profile A) from 405LD34 and white light (profile B) from 445LD32 and phosphor 26 in the special light mode. And a special light color conversion unit 74, a color enhancement unit 76, and a structure enhancement unit 78.
The special light color converting unit 74 assigns a predetermined coefficient to the G image signal of the input preprocessed RGB 3-channel digital image signal and assigns it to the R image data, and multiplies the B image signal by the predetermined coefficient to obtain the G image. After assigning to the data and B image data and generating RGB image data, color conversion such as 3 × 3 matrix processing, gradation conversion processing, and three-dimensional LUT processing is performed on the generated RGB image data in the same manner as the color conversion unit 68. Process.

Similar to the color enhancement unit 70, the color enhancement unit 76 adds a color difference between the blood vessels and the mucous membrane in the screen to enhance the blood vessels so that the blood vessels can be easily seen. A process of looking at the image data while looking at the screen, for example, a process of looking at the average color tone of the entire screen and emphasizing the color tone in the direction of adding a color difference between the blood vessel and the mucous membrane from the average value Do.
Similar to the structure emphasizing unit 72, the structure emphasizing unit 78 performs structural processing such as sharpness and edge emphasis on the color-enhanced RGB image data.
Further, in addition to the structure processing of the structure enhancement unit 72, the structure enhancement unit 78 applies frequency to the above-described color enhancement processed RGB image data based on the shooting information from the shooting information detection unit 56, for example, the AE value. Perform enhancement processing.

The frequency emphasis processing performed here differs depending on the AE value as shown in FIGS. Here, a case where an AE value is used as a representative example of photographing information will be described, but it goes without saying that the present invention is not limited to this.
When the AE value is smaller than the first predetermined value (α), that is, when enlarging observation in which the distal end of the endoscope is close to the subject and the required amount of light may be small is assumed, the superficial microvessel is assumed as an imaging target. Therefore, a frequency enhancement filter capable of enhancing a high-frequency portion as shown in FIG. 5A is applied to the above-described RGB image data so that the structure of the fine superficial microvessels can be individually separated as thin lines.
In addition, when the AE value is in a predetermined range (a range from α to β) between the first predetermined value and the second predetermined value, that is, the endoscope tip is slightly away from the subject and is slightly larger than the magnified observation. When assuming near-field observation that requires light, it is assumed that each of the microvessels that are slightly larger than the subject to be photographed is a fine structure of the superficial microvessel, and the atmosphere of the superficial microvessel is A frequency enhancement filter capable of enhancing the middle frequency portion as shown in FIG. 5B is applied to the above-described RGB image data so that the enhancement is possible.

Further, when the AE value is larger than the second predetermined value (β), that is, when it is assumed that the distal end of the endoscope is away from the subject and a distant view that requires a larger amount of light is required, each surface layer is fine. An area called a brownish brownish area in which superficial microvessels are concentrated and exist as a lump is assumed as an imaging target, instead of blood vessels.
A region called a brownish region is assumed for early cancer and is often about 1 mm, but some are 2 mm and 3 mm. If a bandpass filter is used to emphasize this frequency band, it will not be emphasized if it deviates even slightly from this bandpass band. It is better to use a filter.
Accordingly, when a brownish region is assumed as an imaging target, it is preferable to apply a high-pass filter capable of enhancing the entire high frequency as shown in FIG. 5C to the above-described RGB image data as a frequency enhancement filter. .
The RGB image data subjected to the optimal frequency enhancement processing based on the AE value in the structure enhancement unit 72 is input from the special light image processing unit 64 to the image display signal generation unit 66 as the special light image processed RGB image data. The

The image display signal generation unit 66 receives the image processed RGB image data input from the normal light image processing unit 62 in the normal light mode, and the image processed RGB image data input from the special light image processing unit 64 in the special light mode. Is converted into a display image signal for display as a soft copy image on the monitor 38 or for output as a hard copy image on the recording device 42.
In the normal light mode, the monitor 38 displays a normal observation image as a soft copy image based on a display image signal obtained by the imaging device 26 by irradiating white light and pre-processed by the processor 16 and normal light image processing. In the special light mode, the special light observation image based on the display image signal obtained by the imaging device 26 by irradiating special light in addition to white light and pre-processed and processed by the processor 16 is soft-copied. Display as an image.
The recording device 42 also outputs a normal observation image obtained by irradiating white light in the normal light mode as a hard copy image, and special light observation obtained by irradiating white light and special light in the special light mode. Output the image as a hard copy image.
If necessary, the display image signal generated by the image display signal generation unit 66 may be stored as image information in a storage unit including a memory or a storage device (not shown).

On the other hand, the mode switching unit (input unit) 40 has a mode switching button for switching between the normal light mode and the special light, and the mode switching signal from the mode switching unit 40 is sent to the light source control unit 48 of the light source unit 14. Entered. Here, the mode switching unit 40 is disposed as the input unit 40 of the input / output unit 18, but may be disposed in the processor 16, the operation unit of the endoscope 12, or the light source unit 14. Note that the switching signal from the mode switching unit 40 is output to the light source control unit 48 and the image processing switching 60.
The endoscope apparatus of the present invention is basically configured as described above.

Hereinafter, the operation of the endoscope apparatus of the present invention will be described with reference to FIG.
In the present embodiment, it is assumed that normal light observation is first performed in the normal light mode. It is assumed that 445LD32 is turned on and the normal light image processing unit 64 performs normal light image processing on the captured image data with white light.
Here, the user switches to the special light mode. When the user operates the mode switching unit 40, a mode switching signal (special light ON) is output, and the image processing in the image processing switching unit 60 is switched to the special light mode (S10).

  Next, the mode switching signal is also input to the light source control unit 40 of the light source unit 14, the 405LD 34 is turned on by the light source control unit 40, and white light and narrow band light are simultaneously irradiated toward the subject (S12).

  The simultaneously irradiated white light and narrowband light are reflected by the subject, and captured image information is acquired by the image sensor 26 (S14).

  Next, the captured image information acquired by the imaging element 26 is adjusted in white gain, converted into digital data, and then sent to the light amount calculation unit. As for the captured image information, the light amount calculation unit 50 calculates the brightness (luminance value) of the captured image (RGB image) (S16).

Information on the brightness (luminance value) of the RGB image calculated by the light amount calculation unit 50 is sent to the imaging information detection unit 56, and an AE value for imaging is detected (S18).
Further, instead of the AE value, a shooting magnification in imaging, or subject information (such as the size of a brownish region or the thickness of a blood vessel) may be detected.
The detected AE value is output to the necessary light amount ratio calculation unit 58 and the special light image processing unit 64.

  The required light quantity ratio calculation unit 58 receives the calculated AE value and calculates the required light quantity ratio (S20). As shown in FIG. 4, the necessary light quantity ratio calculation unit 58 includes a table that represents the relationship between the AE value and the LD light quantity ratio, and calculates the LD light quantity ratio according to the AE value.

  The LD light amount ratio is a ratio of the emitted light amounts of 405LD34 and 445LD32, and 445LD32 based on the calculated LD light amount ratio (405LD / 445LD) and the brightness (luminance value) of the captured image calculated by the light amount calculation unit 50. The necessary light amounts of the light amount of 405LD34 and the light amount of 405LD34 are calculated (S22). The calculated required light amount ratio is output to the CDS / AGC 44 for white balance gain adjustment, and the calculated required light amount ratio is output to the light source control unit 48.

  The light source control unit 48 controls the irradiation light amount from 445LD32 and 405LD34 to be the required light amount based on the calculated required light amount of 445LD32 and 405LD34 (S24).

Further, the CDS / AGC 44 adjusts the white balance gain based on the calculated required light amount ratio (S26).
When the amount of light emitted from 445LD32 and 405LD34 changes, the white balance gain also changes accordingly, so that the CDS / AGC is adjusted so that the white balance gain maintains a constant value. Further, instead of adjusting the white balance gain of CDS / AGC, the imaging time or the color tone adjustment of the image processing may be changed.

  Further, the image processing for the captured image is changed based on the AE value calculated by the photographing information detection unit 56 (S28). The image processing changed based on the AE value is performed by the structure enhancement unit 80 of the special light image processing unit 64.

  The captured image information obtained in the narrow-band light observation is output to the special light image processing unit 64, subjected to the above-described image processing through the special light color conversion unit 74 and the color enhancement unit 76, and is sent to the structure enhancement unit 78. Entered. In the structure emphasizing unit 78, the frequency emphasizing filter described in FIGS. 5A to 5C is applied according to the AE value as described above (S30).

In the special light image processing unit 64, the frequency enhancement filter corresponding to the AE value is applied, and the image information subjected to the image processing is output to the image display signal generation unit 66. The image display signal generation unit 66 generates and outputs an image display signal from the image information.
The output image display signal is displayed on the monitor 38 as a special light image and recorded by the recording device 42 (S32).

  Although the endoscope apparatus of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention. Good.

DESCRIPTION OF SYMBOLS 10 Endoscope apparatus 12 Endoscope 14 Light source part 16 Processor 18 Input / output part 22 Optical fiber 24 Phosphor 26 Imaging element 28A Irradiation port 28B Light receiving part 30 Scope cable 32 Blue laser light source (445LD)
34 Blue-violet laser light source (405LD)
36 Image Processing System 38 Display Unit (Monitor)
40 Input section (mode switching section)
42 Recording unit (recording device)
44 CDS / AGC circuit 46 A / D converter (A / D converter)
48 Light source control unit 50 Light amount calculation unit 52 DSP (digital signal processor)
54 Noise removal circuit 56 Shooting information detection unit 58 Required light amount ratio calculation unit 60 Image processing switching unit (switch)
62 normal light image processing unit 64 special light image processing unit 66 image display signal generation unit 68 color conversion unit 70, 76 color enhancement unit 72, 78 structure enhancement unit 74 special light color conversion unit

Claims (18)

A first light source unit that emits narrowband light having a wavelength bandwidth that is narrowed according to the spectral spectrum characteristics of the structure and components of a living body as a subject;
A second light source unit that emits broadband light having a wide wavelength band including the visible region;
The captured image of the subject is captured by return light from the living body of the narrowband light and the broadband light that are simultaneously irradiated onto the subject from the first light source unit and the second light source unit, and the captured image Imaging means for outputting information;
Image processing means for performing predetermined image processing on the captured image information;
Imaging information detection means for detecting, as imaging information, automatic exposure value or imaging magnification for imaging the subject by the imaging means, or subject information related to the structure / component of the living body of the subject imaged by the imaging means; Have
The narrow-band light emitted from the first light source unit is superior in the ability to detect the structure and components of the living body of the subject compared to the broadband light emitted from the second light source unit,
Light emission of the first light source unit and the second light source unit so as to change the degree of detection and enhancement of the structure / component of the living body of the subject based on the photographing information detected by the photographing information detection unit. An endoscope apparatus characterized by changing conditions and image processing conditions in the image processing unit.   Furthermore, in order to change the light emission conditions of the first light source unit and the second light source unit, the light emission ratio between the narrow band light from the first light source unit and the broadband light from the second light source unit The endoscope apparatus according to claim 1, further comprising: a light emission ratio changing unit that changes The imaging information is the automatic exposure value,
The light emission ratio changing means increases the light emission ratio of the narrow-band light from the first light source unit when the automatic exposure value is small, and the broadband from the second light source unit when the automatic exposure value is large. The endoscope apparatus according to claim 2, wherein the light emission ratio is increased. The imaging information is the imaging magnification,
The light emission ratio changing unit increases the light emission ratio of the narrowband light from the first light source unit when the imaging magnification is large, and the broadband light from the second light source unit when the imaging magnification is small. The endoscope apparatus according to claim 2, wherein the light emission ratio is increased.   When the light emission ratio is changed by the light emission ratio changing means, the electrical gain of the image pickup means, the imaging time, and the image are based on the light emission ratio so that the white balance of the captured image does not change. The endoscope apparatus according to any one of claims 2 to 4, wherein at least one of color tone adjustment of processing is changed.   Based on the light emission ratio, when the light emission ratio is changed by the light emission ratio changing means, the electrical gain of the image pickup means, the imaging time, and the image are not changed. The endoscope apparatus according to any one of claims 2 to 5, wherein at least one of color tone adjustment of processing is changed.   The endoscope apparatus according to claim 1, wherein the image processing unit includes an image enhancement unit that changes a frequency enhancement characteristic of the captured image based on the imaging information. The image enhancement means includes frequency band enhancement means for enhancing at least two frequency bands of the captured image,
The endoscope apparatus according to claim 7, wherein the frequency band emphasizing unit changes a frequency emphasis characteristic including changing the frequency band to be emphasized based on the imaging information. The imaging information is the automatic exposure value,
The endoscope apparatus according to claim 8, wherein the frequency band emphasizing unit changes the frequency band to be emphasized to a lower frequency as the automatic exposure value increases. The imaging information is the automatic exposure value,
The frequency band emphasized by the frequency band emphasizing means is a bandpass characteristic,
The endoscope apparatus according to claim 8 or 9, wherein the frequency band emphasizing unit changes the width of the frequency band to be enhanced when the automatic exposure value exceeds a first predetermined value. The imaging information is the automatic exposure value,
The frequency band emphasizing unit sets the frequency band to be emphasized to a band pass characteristic when the automatic exposure value is equal to or smaller than a second predetermined value, and changes to a high pass characteristic when the frequency exceeds the second predetermined value. The endoscope apparatus according to any one of Items 8 to 10. The imaging information is the imaging magnification,
The endoscope apparatus according to claim 8, wherein the frequency band emphasizing unit changes the frequency band to be emphasized to a higher frequency as the imaging magnification increases. The imaging information is the subject information related to the size of a brownish region or the thickness of a blood vessel,
The endoscope apparatus according to claim 7, wherein the image enhancement unit changes a frequency enhancement characteristic of the captured image based on a size of the brownish region or a thickness of the blood vessel. The image enhancement means includes frequency band enhancement means for enhancing at least two frequency bands of the captured image,
The endoscope apparatus according to claim 13, wherein the frequency band emphasizing unit changes frequency emphasis characteristics including changing the frequency band to be emphasized based on a size of the brownish region or a thickness of the blood vessel. .   The endoscope apparatus according to claim 14, wherein the frequency band emphasizing unit changes the frequency band to be emphasized to a higher frequency as the thickness of the blood vessel becomes smaller.   The frequency band emphasizing means emphasizes when the size of the brownish region is a predetermined size or less, the frequency band to be emphasized has a bandpass characteristic, and emphasizes when the size of the brownish region exceeds the predetermined size. The endoscope apparatus according to claim 14, wherein the endoscope apparatus is changed to increase the width of the frequency band.   The endoscope apparatus according to claim 1, wherein the photographing information detection unit detects the photographing information from the photographed image.   The endoscope apparatus according to claim 17, wherein the photographing information detection unit detects the automatic exposure value from the brightness of the photographed image.

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